Fluid system



Jan. 3, 1933. D. F. COMSTOCK FLUID SYSTEM Filed Dec. 17, 1930 2 Sheets-Sheet 'fm/eiztor flail '9! FC m sityk. J Aug.

Jan. 3, 1933. D. ,F. COMSTOCK FLUID SYSTEM 2 Sheets- Sheet 2 Filed Dec. 17. 1930 In ventar.

Daniel 17 0272.;

Pu a-J Ja 3, 1933 UNITED srA'rEs PATENT OFFICE DANIEL I. GOIBTOGK, OF BOSTON, ILSSACHUBE'I'I'S, ASBIGNOIR TO GOIBTOGI Q WESOOTT, INC, 01' BOSTON, MASSACHUSETTS, A CORPORATION 01' IASSAOHUSEI'TS FLUID stem Application filed December 11, mo. man in. 502,955.

This invention relates to an improved heat exchange system and method, and more particularly to refrigerating apparatus of the balancing liquid column; for example, this invention may be advanta ously employed in a refrigerating system 0 the character disclosed in the Patent No. 1,761,551 to Eastman A. Weaver, dated June 3, 1930, which discloses a system employinga relatively heavy and non-volatile ropellant such as mercury and a lighter'an more volatile refri rant such as water, the propellant being e ective in causing the circulation of refrigerant from a cooler to a condenser.

In accordance with the resent invention, means is provided to permit the system to be compact, and the pessure balancing column of propellant to relatively high, i. e. to have .its' upper end substantially above the propellant condenser, so that the boiler pressure may be correspondingly high and the system have a higher refrigeratin capacity, i. e. mercury vapor may be suppli at higher pressure to the aspirator nozzle, where it is effective in entraining refrigerant vapor from the cooler, compressing the same and pumping the same to the refrigerant condenser. In order to permit this desirableresult the present invention provides a lifter or means to raise condensed propellant from the propellant condenser to the upper end of a return pipe which may extend to a height substantially above the condenser. Preferably such lifter comprises a lifter tube of restricted diameter which may be supplied with the condensed propellant and with vapor under suflicient pressure to break ofl successive propellant globules and lift the same, it being understood that the'diameter of the lifter tube is so determined that the propellant will form separate globules wetting the entire internal surface of a crosssectional portion ofthe tube, thus being readily lifted by the vapor injected into the lower part of the tube. Preferably refrigerant obtained, for example,-f rom the refrigerant condenser, may'be employed thus to lift the propellant, heat being supplied to the refrigerant which is thus shunted from the main refrigerant circuit to cause the vapor enterin the lifter tube to have sufiicient pressure to ift the propellant to the upper part of the system, the refrigerant being returned from the upper part of the lifter tube tothe main refrigerant circuit and the propellant being directed to the upper part ofthe propellant return pipe.

In the accompanying drawings:

Fig. 1 is a side elevational view of a portion of a refrigerating apparatus, more or less dia rammatical in character, with parts bro en away and in section and certain parts removed for clarity of illustration;

Fi 2 is-a.vie'w, partly in elevation and part1? in section, of secondary pumping means that may be employed to supply refrigerant to a vaporizer which is connected to the propellant lifter tube;

Fig. 3 is anelevational view of the refrigerant vaporizer;

Fig. 4 is a sectional view of a metering device which is efi'ective in-supplying a portion of the'lifted ropellant to the propellant re turn pipe an a portion thereof to the secondary pumping means and other auxiliary parts of the system such as a purger and a refrigerant lifter; and

Fig; 5 is a broken diagrammatical view of the cooler and relating ipe.

In accordance with t e present invention, vapor may be introduced into a lifter tube of restricted diameter to lift slugs of liquid which has been condensed and to direct the same to the upper part of the system where the lifted liquid or the major portion of the same may be directed to the upper end of a return pipe which contains a pressure balancing liquid column which has its lower end connected to the boiler. More specifically the invention is applicable to a system employing a relatively heavy liquid of low volatility such as mercury for a propellant and lighter, more volatile liquid such as water as a refrigerant, the circuits for the respective liquids having a part in common where the propellant is effective in causing the circulation of the refrigerant. In a system of this character, 1 consider it preferable to supply refrigerant vapor to the lower part of a litter tube of restricted diameter, and to supply sufificient heat to this refrigerant so that its pressure is high enough to lift the propellant to the upper part of the system. For purposes of convenience in illustration, I have illustrated the invention as applied to a system of the general character disclosed in the patent to Eastman A. Weaver, identified above, and have shown this arrangement in conjunction with a supply pump and other improvements which are more particularly disclosed and claimed, in the copending application of Lyman 1F. Whitney, Serial No. 503,006, filed on even date herewith.

In the accompanying drawings numeral 1 designates a boiler which may be conveniently associated with a heating factor 4, such as a concentrically disposed fuel burner, which is arranged to emit a combustible mixture into a combustion chamber associated with the boiler and communicating with an upwardly extending flue 6 for exhaust gases. The boiler is connected to an outlet pipe 15 which may extend upwardly to an aspirator nozzle 16 and may include an expansible, contractible portion 17 such as a metal bellows to avoid undue strain upon the aspirator nozzle. Propellant such as mercury is vaporized in the boiler 1 and passes upwardly through duct 15 and nozzle 16 which projects into a mixing or entraining chamber 20. A duct 21 connects this chamber with the upper part of cooler 12, Fig. 5. Accordingly propellant vapor leaving nozzle 19 at high velocity entrains refrigerant vapor in chamber 20, thus causing evaporation of the refrigerant in the cooler and a resulting low temperature of the latter. The mixture of propellant and refrigerant vapors passes from chamber 20 to funnel 25 which is aligned with nozzle 19 and may be provided with suitable cooling fins 26. Thus the propellant vapor may be condensed at its comparatively high temperature of liquefaction, as the energy of the same is exhausted in compressing the refrigerant vapor. Since the temperature of funnel 25 is well above the temperature of condensation of refrigerant vapor at pressure conditions prevailing in this part of the system, the refrigerant vapor passes out of the funnel through the upwardly extending vapor duct 36 which is connected to a refrigerant condenser 40, sub stantially above its lowermost portion. The refrigerant condenser 40 may be of any suitable type, for example, being supplied with heat radiating or dissipating elements such as fins, which are not shown. A drain 38 may be connected to the lowest part of the condenser 40 to receive liquid refrigerant therefrom.

neeaero Suitable drains are provided to receive condensed propellant from the mixing chamber 20 and funnel 25. For example, the drain 31 may be connected to the lower part of the mixing chamber to collect any particles of propellant which may have condensed in this part of the system, while drain 32 may be connected to the lower portion of the inclined funnel 25 and receive the major portion of the condensed propellant from the same and the adjoining vapor duct 36. The drain 31 may conveniently extend downwardly to a main propellant collecting duct or trap 50 which is disposed adjoining the boiler l. The upper end of a downwardly extending pipe 45 communicates with drain 32 below its connection with funnel 25 and forms one leg of a trap 46 adjoining the lower part of the apparatus, the opposite leg of this trap being designated by numeral 47 and extending upwardly to a pipe 70. Downwardly extending pipe 48 of relatively large diameter joins the upper part of pipe 45 with the duct or trap 50.

Secondary pumping means, which may receive refrigerant from the condenser 40 and direct the same to the propellant lifter tube, is designated by numeral 49. For this urpose the duct 38 is arranged to supply re rigerant to a chamber 51, Fig. 2. Mercury 1s supplied to this chamber from one leg 52 of a trap 53 in a manner which will presently be described. The major portion of a tube 54 extending downwardly from chamber 51 to a separating chamber 55 has a restricted internal diameter so that condensed refrigerant passing downwardly through the same may be entrained between bodies or globules of the propellant which act as separate liquid pistons, while the upper portion 54 of tube 54 has a somewhat greater diameter and is received in the chamber 51. A duct 56 has an open end in the upper part of separating chamber 55 and a duct 57 has an open end below the end of duct 56, but above that of tube 54, so that the lighter refrigerant rising to the upper part of the chamber normally passes into duct 56 and the heavier propellant normally passes into duct 57 while the lower end of tube 54 is always submerged in propellant and sealed against entry of refrigerant. A suitable by-pass duct 80 connects the entr'ain'ing chamber 51 with the duct 57 below the separating chamber 55. Duct 56 is connected to one end of the upwardly extending duct (Fig. 7) that communicates with a secondary boiler designated in general by numeral 71; this boiler is juxtaposed to flue 6 and comprises a small reservoir 72 which is connected to an outlet tube 73 of restricted internal diameter having a plurality of helical windings disposed about the funnel 6. A continuation 74 of tube 73 is connected to an upwardly extending lifter tube 75 ofrestricted diameter which forms a continuation of pipe 50. It is evident that the refrigerant entrained in the tube 54 normally separates from the propellant in the separating chamber 55 and passes through pipes 56 and to the reservoir 72. The latter is in direct heat transfer relation to the fine 6, and accordingly the refrigerant is vaporized in this part of the system either in the reservoir or the tube 70 or the tube 73; the latter affords a considerable frictional resistance to the rapid flow of the refrigerant vapor, and accordingly the quantity of vapor which may thus flow through the secondary va orizer 71 is restricted. The vapor passing into tube 75 breaks ofi mercury bodies and is effective in lifting the same through tube 7 5 to a separating chamber 82. An inclined pipe 83, shown in dotted lines in Fig. 1, connects. the upper portion of the latter to the refrigerant condenser so that the refrigerant vapor received from tube 75 may pass into the refrigerant condenser, there rejoining the main refrigerant circuit and being condensed.

The liquid propellant passes from the bottom of chamber 82 into a trap 183, a continuation 84 of which is joined to a propellant dividing factor 100. The latter is illustrated in greater detail in Fig; 4 and comprises an outer cylindrical shell and an inner cylindrical member 91 of less height, the walls of the members 90 and 91 being spaced from each other and a sheet metal member 89, having spiral convolutions, being disposed between the members 90 and 91 and thus providing inner and outer spiral passages 92 and 93. The inner passage 92 communicates with the chamber 94 which is above the member 91, so that mercury entering the chamber through pipe 84 may pass downwardly through passage 92 and through .an opening or notch 95 at the lower end of the shell and thence upwardly through the outer spiral passage 93 which communicates with the outlet duct 97. It is evident that spiral passages 92 and 93 afford considerable re sistance to the flow of the mercury, and accordingly that the same tends to pile up above the member 91 and overflows-into the passage 101 in the central part of the latter. Thus the factor is eiiective in supplying a fixed or limited quantity of propellant to the secondary pump through the duct 97 and in permitting the remainder of the propellant to pass downwardly through passage 101, which communicates with a propellant return pipe 102. The latter is disposed adjoining the flue 6 and has its lower end communicating with the boiler through a connection 103. An opening 109 may be disposed in the upper part of the sheet metal element 89 to permit the pressures at opposite sides of the same to be equalized, and a suitable inwardly bent tab 106 is disposed adjoining the mouth of-duct 84 to preventincoming mercury from passing directly to passa e 101.

ercury from duct 97 passes to trap 53 which is connected through duct 52 to the entraining chamber 51 of the secondary pumping means, a suitable cylindrical screen 115 is arranged about the upper end portion 54 of tube 54 in the chamber 51 and a closure plate 116 is disposed over the top of member 115 and opening 117 may be provided in the side of the tube portion 54 that projects into the chamber; thus mercury may pass into the tube and flow down the same due to its restricted internal diameter in the form of successive liquid globules which entrain bodies of the lighter refrigerant therebetween. -The screen 115 is effective in preventing the clogging of the tube 54 with foreign matter. Mercury leaving the separating chamber 55 of the secondary pumping means normally passes into the tube 57 which comprises one leg of a trap 58, the opposite' leg 58 of which is connected to an entraining chamber 150 that is disposed above chamber 55.

The internal arrangement of chamber 150 may be similar to that of chamber 51 and a drain 152 that is connected to the refrigerant condenser above the outlet 38 may be joined to the upper part of chamber 150. Thus, while condensed refrigerant is preferentially supplied to the secondary pumping means 49 and thence to the vaporizer 41 and the propellent lifter, during normal operation ofvthe system the refrigerant in the con denser will not only flow to the secondary pumping means 19 but it will alsofiow through pipe 152 to chamber 100. The lower portion of the-latter receives the upper end of a tube. 153 of restricted diameter, wherein propellent globules may entrain bodies of the condensed refrigerant, subjecting the same to a considerable liquid head at the lower end of tube 153, which is joined to a separating chamber 155. The tube 153 has an open and disposed adjoining the bottom of this chamber and the refrigerant outlet pipe 158 communicates with the upper part of the chamber. Thus the lighter refrigerant separates from the propellant and passes upwardly through duct 158 under suitable pressure, so that it may be returned to the cooler 12 that is disposed above the remainder of the system; for example, the maior portion of the apparatus may be 1nstalled in the basement and the cooler may be disposed. within a refrigerator upon the first floor. As shown in Fig. 5, the bottom of the cooler 12 preferably inclines downwardly to the tube 158 which is joined to the lowest corner'of the cooler, so that stray propellent particles that pass into the cooler will flow downwardly through tube 158 and thus be received by separating chamber 155.

Preferably the lower part of tube 158 is flattened, being provided with such a shape and dimensions that mercury globules will not form in the same and close its entire area so as to rise with the refrigerant. The-open end of a duct 160 is disposed within chamber 155 at a height between the end of tube 153 and the mount of pipe 158 so that mercury the main propellant collecting pipe 50, while tube 153, having its lower end always 1mmersed in mercury, is permanently sealed against blowing back of any refrigerant due to fluctuating pressures.

In order to aid the thermal efliciency of the system the pipes 75 and 102 are disposed adjoining the flue, which is at a comparatively high temperature when the system is in normal operation. The flue and these pipes preferably are enclosed within a cylindrical casing 170 which may contain suitable powdered insulating material, such as 'silocel or infusorial earth. A rectangular casing 261, also containing suitable heat insulating material may be joined to the lower part of the cylindrical casing 170 in which the mixing chamber 20, the propellent vapor duct 15 and the boiler 1 are enclosed. Heat losses are accordingly minimized and the hot portions of the system are effectively insulated. It is evident that the funnel 25 projects from the casing 261 and that the outer portion of the burner 4 which is connected to the gas supply duct projects from the wall of the casing.

. In the operation of a system of this character, propellant such as mercury is vaporized in the boiler 1, passing upwardly through duct 15 to aspirator nozzle 16. Vapor duct 21 permits refrigerant vapor to be rapidly drawn from cooler 12 to mixing ehamber 20 of the outlet of aspirator nozzle 16. Accordingly the temperature of the cooler may be low to provide refrigeration.

The major port-ion of the propellent vapor from nozzle 16 is condensed in funnel 25 and the refrigerant Vapor passes through duct 36 to refrigerant condenser 40. The propellant from funnel 25 passes into drain 32 and thence through pipe 48 to the main propellant collecting pipe 50, while drain 31 receivespropellant which is condensed in the mixing chamber and supplies the same to pipe 50. The propellant may pass from drain 32 directly through a portion of pipe 45 to duct 48 and thus to the main propellent collecting duct 50, since the trap 46 is normally filled with propellant substantially to its juncture with pipe 48.

During normal operation of the system, refrigerant is vaporized in the secondary boiler 71; the flow of this vapor is somewhat limited due to the restricted diameter of tubes 73, as it passes into the lower end of pipe 75, there being effective in breaking off successive globules of mercury and lifting the same to the separating chamber 82. The refrigerant vapor rises to the upper part of this chamber and passes from the same through pipe 83 to the refrigerant condenser, there rejoining the main refrigerant circuit. The lifted propellant passes to the lower part of the chamber 82, being received by the pipe 83 and passng through its connection 84 to the separating factor 1.00. As has already been described, this factor is effective in preferentially diverting a portion of the lifted mercury to the pipe 97 and trap 53, while the remaining portion of the mercury or the propellant is returned through pipe 102 directly to the boiler; it being evident that the pipe 102 contains a liquid column of the propellant to balance the boiler pressure. Mercury from duct 97 passes through trap 53 and duct 52 to the entraining chamber 51 of the secondary pumping means 49. Liquid refrigerant is there received through pipe 38 from the bottom of the condenser 10 and is supplied to separating chamber 55, thence passing through tube 56 and pipe to the secondary boiler 71. Accordingly it is evident that the pumping means 49 is effective in supplying liquid refrigerant to the secondary vaporizer under an appreciable liquid head due to the weight of the mercury globules in the tube 54.

Mercury passing from chamber 55 into trap 58 is received by the entrainingchamber 150 of the refrigerant lifter which is supplied with refrigerant from the condenser, and the mercury globules passing downwardly in tube 153 are effective in imposing a suitable head upon the condensed refrigerant, so that the latter, when separated from the mercury in chamber 155, may rise through tube 158 to the cooler; the mercury passes downwardly through trap 151 and fills the leg of the latter which is provided by drain 32 until it overflows into the upper part of pipe 45. thence passing to pipe 48 and the main collecting pipe 50 and in this way re joining the main propellent circuit.

It is evident that all parts of the system are arranged so that stray propellant may be returned to the propellant containing part of the svstem. Thus propellant passing to the refrigerant condenser may be received by the drains 37 and 38 and thus pass into the entraining chamber 51. while the cooler is so shaped that stray mercury passing to the same will return through pipe 158.

From the foregoing it is evident that this invention provides an arrangement permitting condensed fluid such as propellant to be lifted to the top of a pressure balancing liq 'uid column that balances the boiler pressure and is effective in returning the condensed liquid to the boiler. Accordingly a system provided with an arrangement of the character disclosed herein may be relatively compact and yet have a boiler pressure high enough to permit eflicient and satisfactory operation.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. Apparatus of the class described comprising a propellant circuit and a refrigerant circuit, a boiler in the former and a cooler in the latter, said circuits having a common part Where vaporized propellant causes the refrigerant to circulate, means receiving the propellant from said common part and lifting it to a region above the same, and a return pipe forming part of the propellant C11- cuit and containing a liquid column which receives the propellant thus lifted and returns the same to the boiler.

2. Apparatus of the class described comprising a propellant circuit, a boiler in said circuit, heating means associated with said boiler, a refrigerant circuit including a cooler and a refrigerant condenser, a propellant condenser in the propellant circuit, said circuits having a common part where vaporized ropellant causes the circulation of the rerigerant through its circuit, means in heat transfer relation to the heating means for the boiler and adapted to receive liquid from one of said condensers and to cause the vaporization of the same, said means receiving liquid propellant and being adapted to impart sufiicient pressure thereto to return it to the boiler. I

3. The method of refrigeration which comprises circulating a propellant through a a circuit which includes a propellant vaporizer thereb causing the circulation of a refri erant t rough a refrigerant circuit that inc udes a cooler, a refrigerant condenser and a part where energy is imparted by the propellant to the refrigerant, condensing the propellant after it has thus imparted energy to the refrigerant, directing the condensed propellant to a region in heat transfer relation to the boiler and there employing the heat to vaporize a portion of the liquid from one of said condensers to cause an increase in pressure and employing said pressure to effect the return of the liquid propellant to the boiler.

4. The method of refrigeration which comprises vaporizing a propellant to circulate the'same through a propellant circuit, employing the vaporized propellant to entrain refrigerant from a cooler, condensing the ropellant, directing the condensed propelant to a tube of restricted diameter, condensin the refrigerant separately from the prope lant, directing a rtion of the, condensed refrigerant to a region where it may be re-' vaporized; directing the revaporized portion of the refrigerant to the tube of restricted diameter and employing the pressure of this refrigerant vapor to cause the upward movement of globules of liquid propellant in the tube, collecting propellant thus lifted at the upper end of a pressure balancing column and returning pro llant from the lower end of the same to t e vaporizer, and returning refrigerant vapor from the tube to the mam refrigerant circuit.

5. The method of refrigeration which comprises employing the vapor of a relatively heavy propellant of high boiling point in entraining a lighter, more volatile refri erant from-a cooler and causing the circulation of the refrigerant through a refrigerant condenser, condensing the propellant at a temperature above the temperature of condensation of the refrigerant, directing the condensed propellant to the lower end of a passage of restricted diameter, emplo ing refri erant vapor to lift the propellant t rough sai tube directing the propellant from the upper end of the tube to a. pressure balancing column of the same, where y the propellant is returned to the vaporizer, and returning the refrigerant vapor from the tube to the main refrigerant circuit.

6. Apparatus of the class described comprising a propellant circuit including a boiler and containing a propellant of low volatility, a refrigerant circuit includin a cooler and containing a relatively volati e refrigerant, said circuits having a common part, where the propellant vapor from the boiler is effective 1n circulating the refrigerant, a propellant condenser in the propellant circuit, and a refrigerant condenser in the refrigerant circuit, a propellant return duct with its upper end disposed above the propellant condenser, and lifting means receiving the propellant from the propellant condenser and lifting the same to the upper end of said re turn duct, said means including an upwardly extending tube of restricted diameter wherein propellant is lifted in separate globules, and a refrigerant duct connected to said tube and the refrigerant condenser, said refrigerant duct being arranged to supply refrigerant in its vapor phase to thelower end of the tube, whereby the refrigerant vapor lifts propellant to the upper end of the return duct. 1

7. Apparatus of the class described comprising a propellant circuit including a boiler and containing a propellant of low volatility, a refrigerant circuit includin a cooler and containing a relatively volati e refrigerant, said circuits having a common part, where the pro ant va or from the boiler is efv fective m circulating the refrigerant, a propellant condenser in the-propellant circuit, and a refrigerant condenser in the refrigerant circuit, a propellant return duct with its upper end dlsposed above the propellant condenser, and lifting means receiving the propellant from the propellant condenser andliftin the same to the upper end of said re- 1 turn uct, said means including an upwardly extendin tube of restricted diameter wherein (Fmpe ant is lifted in separate globules, an a duct receiving fluid from one of said condensers and arranged to supply the fluid in its vapor phase to the lower end of the tube, whereby the vapor lifts propellant to the upper end of the return duct.

Signed by me at Boston, Massachusetts, this 15th day of December, 1930. DANIEL F. COMSTOCK. 

